In the practice of diagnostic medicine, it is often necessary or desirable to perform a biopsy, or to sample selected tissue from a living patient for medical evaluation. Cytological and histological studies of the biopsy sample can then be performed as an aid to the diagnosis and treatment of disease. Biopsies can be useful in diagnosing and treating various forms of cancer, as well as other diseases in which a localized area of affected tissue can be identified.
During the biopsy procedure, care is taken to minimize the physical trauma inflicted upon the intervening tissues that surround the affected area or target tissue and at the same time to protect the practitioner from health hazards. One typical biopsy procedure includes inserting a hollow biopsy needle through the intervening tissue into the target tissue to be sampled. The sample tissue is then harvested through the needle by applying suction through the needle, typically with a syringe.
Other more complicated devices have been developed in an attempt to improve biopsy procedures and results. Three references, U.S. Pat. No. 5,301,684 to Ogirala; U.S. Pat. No. 5,424,376 to Banys et al.; and U.S. Pat. No. 5,224,488 to Neuffer disclose biopsy devices employing lateral openings. The Ogirala reference shows a cutting edge on a spring operated flap over the lateral opening. The Neuffer device includes a twisted flexible cutting strip contained within the needle. Turing a handle flexes the strip through the lateral opening. The surgeon then rotates the device to cut a sample and guide it into the needle. The Banys patent discloses a biopsy needle attached to a syringe having a cannula which is slidable over the needle to alternately expose or cover the lateral opening. Both the cannula and the lateral opening provide a tissue cutting edge. Using the Banys device, the surgeon is required to maneuver the needle so that the sample is placed within the needle and then slide the cannula to cover the lateral opening and trap the sample within the needle.
Another reference of interest, U.S. Pat. No. 3,001,522 to Silverman, discloses a biopsy device having a pair of resilient arms which extend from the end of the device. The arms are disposed at an angle away from the axis of the device and are oppositely beveled to urge the arms apart as they are inserted into tissue. The Silverman device does not include a side port or a ramp for exit of a biopsy needle from an introducer device.
The prior art biopsy procedures and devices suffer from several disadvantages. First, they do not adequately address the need for multiple samplings. It is often desirable to sample the tissue surrounding a lesion in addition to the lesion itself. Also, needle aspiration biopsies are prone to sampling errors, which necessitate reinsertions of the biopsy needle.
Furthermore, none of the known prior devices accommodate the need to reach behind vital organs and structures because they require a straight path to the target. Current systems require multiple device insertions to sample tissue eccentric to the initial needle placement. Unfortunately, multiple insertions of the biopsy device increase patient discomfort, surgical time and the risk of complications.
Another important consideration in biopsy needle design is that the amount of tissue harvested be sufficient for the types of analysis to be done. Although major improvements have been made in the sensitivity of test procedures and apparatus so that smaller samples have become sufficient for each test, the number of different test procedures and the importance of having the capability for redundant or confirming testing still necessitates having a suitable sample size. However, the size of the tissue sample is limited by the size of the opening in the sampling end of known biopsy needles. Where the size of the tissue collected is inadequate, multiple device insertions will be required. This is often complicated by the difficulty in returning to the exact location required as well as the increased trauma to the patient.
Current systems are also limited in that they cause unnecessary trauma to the patient. For example, lesions located behind important vascular structures are difficult to reach without causing damage. Also, pushing a hollow needle through intervening tissues to the target area results in the accumulation of unwanted tissue in the needle, which can interfere with or complicate sample analysis. Finally, the open end of a biopsy needle or the projecting edge of a cutting cannula can tear the surrounding tissue unnecessarily, increasing trauma to the patient.
Current systems that attempt to address some of these concerns are generally complicated spring-operated or multi-component devices. Furthermore, these devices require multiple insertions for sampling eccentric to the initial device placement. Accordingly, a need has remained for biopsy devices which compensate for sampling errors and accommodate the need for safely and efficiently obtaining multiple samples with a single device placement.
Once pathology is diagnosed, the site must be accessed for treatment. Conventionally, malignancies are treated indirectly by chemotherapy and/or radiation or directly by removal of the lesion. Each of these approaches has limitations and undesirable side effects. Surgery carries risks of infections and adverse anesthesia effects and does not always improve the outcome. Surgery may not be an option due to patient condition or the location and size of the tumor. Furthermore, some studies have suggested that surgery may be associated with the spread of some cancers. Chemotherapy and radiotherapy affect both normal and malignant dividing cells, leading to, for example, hair loss, nausea and decreases in all blood cell types. In spite of the emotional and physical costs paid, conventional treatments do not always increase length of survival or quality of life of patients.
Percutaneous procedures are now favored for their reduced risks and trauma. Ideally, conditions would be treated locally through a single port instead of systematically. Such treatments would be more precise as well as less traumatic and invasive. Various conditions have been treated percutaneously with some success using such methods as mechanical, chemical and radio-ablation. One limitation of these known procedures is the accuracy of needle placement.
Transperineal radioactive seed implantation show great promise for treating prostate cancer (Grimm et al., New Techs in Pros. Surg. 2:113-126, 1994). This percutaneous, outpatient treatment provides more precise and effective dosing than open approaches with lower morbidity than external beam radiation. While this procedure represents a major advance in treating prostate cancer, improvements are still needed in obtaining reproducible and accurate needle placements. The methods involve multiple needle placements and removal. A depth reference point must be calculated by measuring the distance from the hub of the needle for each placement. It is important that the needle and seed placement be precise. Needle placements of more than 1-2 mm off the targeted coordinate must be repositioned. Needle placements that are otherwise on target must be repositioned if the needle insertion causes lateral rotation of the prostate. This procedure also requires at least two surgeons for manipulation of the needles and stylets to prevent improper deboarding of the pellets.
Percutaneous fine-needle alcohol ablation has also been used with some success in the treatment of tumors. Karstrup et al. (AJR: 154: 1087-1090, 1990) disclose ablation of parathyroid tumors under ultrasonographic guidance. Precise needle placement is essential due to the important neurological and vascular structures in the area. The authors recommend small amounts of alcohol and precise placement of the needle tip to avoid nerve damage.
Accordingly, there is a need for less invasive and traumatic and yet more precise, efficient and localized treatments of lesions.